I agree with what everyone above said. I had a 7.1 set up with a couch against the back wall for a couple of years. I pointed the speakers (which sat on shelves) straight up into the ceiling and allowed them to reflect down into the listening area. Not an optimal set-up to say the least.
Could you detect when the "6 & 7" in the 7.1 were active? Yes. Did it help round out the back soundtage? Maybe. Now that I've moved and gotten rid of the back 2 speakers, can I tell the difference? No.
I think I mostly did the 7.1 just to say I had it. Sonic improvements were minimally, if at all, detectable.
I concur with the suggestion to upgrade to the quad-pole and ditch your di-poles. Never been a big fan of the di-pole speakers.
